add githash file to setup, manifest and gitignore

.gitignore

@@ -19,6 +19,7 @@ xonsh.egg-info/
 docs/_build/
 docs/envvarsbody
 docs/xontribsbody
+xonsh/dev.githash
 
 # temporary files from vim and emacs
 *~

MANIFEST.in

@@ -1 +1,2 @@
 include logo.txt
+include githash

setup.py

@@ -7,6 +7,7 @@ from __future__ import print_function, unicode_literals
 import os
 import sys
 import json
+import subprocess
 
 try:
     from tempfile import TemporaryDirectory
@@ -101,11 +102,47 @@ def install_jupyter_hook(prefix=None, root=None):
             d, 'xonsh', user=user, replace=True, prefix=prefix)
 
 
+def dirty_version():
+    """
+    If install/sdist is run from a git directory (not a conda install), add
+    a devN suffix to reported version number and write a gitignored file
+    that holds the git hash of the current state of the repo to be queried
+    by ``xonfig``
+    """
+    try:
+        _version = subprocess.check_output(['git', 'describe', '--tags'])
+        _version = _version.decode('ascii')
+        try:
+            base, N, sha = _version.strip().split('-')
+        except ValueError: #on base release
+            open('xonsh/dev.githash', 'w').close()
+            return
+    except subprocess.CalledProcessError:
+        return
+
+    replace_version(base, N)
+    with open('xonsh/dev.githash', 'w') as f:
+        f.write(sha)
+
+
+def replace_version(base, N):
+    """Replace version in `__init__.py` with devN suffix"""
+    with open('xonsh/__init__.py', 'r') as f:
+        raw = f.read()
+    lines = raw.splitlines()
+    lines[0] = "__version__ = '{}.dev{}'".format(base, N)
+    upd = '\n'.join(lines) + '\n'
+    with open('xonsh/__init__.py', 'w') as f:
+        f.write(upd)
+
+
 class xinstall(install):
     """Xonsh specialization of setuptools install class."""
     def run(self):
         clean_tables()
         build_tables()
+        # add dirty version number
+        dirty_version()
         # install Jupyter hook
         root = self.root if self.root else None
         prefix = self.prefix if self.prefix else None
@@ -123,9 +160,11 @@ class xsdist(sdist):
     def make_release_tree(self, basedir, files):
         clean_tables()
         build_tables()
+        dirty_version()
         sdist.make_release_tree(self, basedir, files)
 
 
+
 #-----------------------------------------------------------------------------
 # Hack to overcome pip/setuptools problem on Win 10.  See:
 #   https://github.com/tomduck/pandoc-eqnos/issues/6
@@ -155,6 +194,7 @@ if HAVE_SETUPTOOLS:
         def run(self):
             clean_tables()
             build_tables()
+            dirty_version()
             develop.run(self)
 
 
@@ -192,7 +232,7 @@ def main():
         packages=['xonsh', 'xonsh.ply', 'xonsh.ptk', 'xonsh.parsers',
                   'xonsh.xoreutils', 'xontrib', 'xonsh.completers'],
         package_dir={'xonsh': 'xonsh', 'xontrib': 'xontrib'},
-        package_data={'xonsh': ['*.json'], 'xontrib': ['*.xsh']},
+        package_data={'xonsh': ['*.json', '*.githash'], 'xontrib': ['*.xsh']},
         cmdclass=cmdclass,
         scripts=scripts,
         )